River braces for his grandfather's funeral. Lamb looks into the passing of an ex-Slow Horse.

The reemergence of Frank Harkness and a suspicious string of cuddles put Lamb and team on high alert.

Ex-Slow Horses return to the fold as assassins close in. Taverner faces the fallout of her TV interview.

Lamb tries figuring out who Frank is working for. Sid, River, and Coe do everything to evade the hit squad.

River goes after Sid. Lamb sets his sights on Cantor. Taverner carries on with a treacherous deal.

Season finale. The safe house becomes unsafe as Lamb and Taverner finally join forces.